Fungicide mixtures

ABSTRACT

Fungicidal mixtures, comprising
         A) imidazole derivatives of the formula I       

     
       
         
         
             
             
         
       
         
         
           
              in which R 1  and R 2  are halogen or phenyl, which may be substituted by halogen or alkyl, or R 1  and R 2  together with the bridging C═C double bond form a 3,4-difluoromethylenedioxyphenyl group; R 3  is cyano or halogen, and R 4  is dialkylamino or isoxazol-4-yl, which may carry two alkyl radicals; and 
             B) valinamides of the formula II, 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
              in which
           R′ is phenyl, which is substituted in the 4-position by halogen, C 1 -C 4 -alkyl or C 1 -C 4 -alkoxy,    is 1- or 2-naphthyl, or   
         
              is benzothiazol-2-yl, which is substituted in the 6-position by halogen; and
           R″ is C 3 -C 4 -alkyl;
 
in a synergistically effective amount, methods for controlling harmful fungi using mixtures of the compounds I and II and the use of the compounds I and the compounds II for preparing such mixtures are described.

The present invention relates to fungicidal mixtures, comprising

-   -   A) imidazole derivatives of the formula I

-   -    in which R¹ and R² are halogen or phenyl, which may be        substituted by halogen or C₁-C₄-alkyl, or        -   R¹ and R² together with the bridging C═C double bond form a            3,4-difluoromethylenedioxyphenyl group;        -   R³ is cyano or halogen, and        -   R⁴ is di(C₁-C₄-alkyl)amino or isoxazol-4-yl, which may carry            two C₁-C₄-alkyl radicals; and    -   B) valinamides of the formula II,

-   -    in which        -   R′ is phenyl, which is substituted in the 4-position by            halogen or C₁-C₄-alkyl or C₁-C₄-alkoxy,        -    is 1- or 2-naphthyl, or        -    is benzothiazol-2-yl, which is substituted in the            6-position by halogen; and        -   R″ is C₃-C₄-alkyl;    -   in a synergistically effective amount.

Moreover, the invention relates to methods for controlling harmful fungiusing mixtures of the compounds I and II and to the use of the compoundsI and the compounds II for preparing such mixtures.

The imidazole derivatives of the formula I, their preparation and theiraction against harmful fungi are known from the literature (EP-A 298196, WO-A 97/06171).

The valinamides of the formula II and processes for their preparationare described in EP-A-0 398 072, EP-A-0 610 764, DE-A-43 21 897,WO-A-96/07638 and JP-A 09/323984. Moreover, they can be preparedsimilarly to the processes described in DE 1 95 31 814.

It is an object of the present invention to provide mixtures which havean improved activity against harmful fungi combined with a reduced totalamount of active compounds applied (synergistic mixtures), with a viewto reducing the application rates and improving the activity spectrum ofthe known compounds I and II.

We have found that this object is achieved by the mixture defined at theoutset. Moreover, we have found that applying the compounds I and thecompounds II simultaneously, that is either together or separately, orapplying the compounds I and the compounds II successively providesbetter control of harmful fungi than is possible with the individualcompounds alone.

The formula I represents in particular imidazole derivatives of theformula I in which R¹ is halogen, in particular chlorine, and R² istolyl, in particular p-tolyl.

Likewise, preference is given to compounds of the formula I in which R⁴is dimethylamino.

In addition, particular preference is given to the compound of theformula Ia (common name: cyazofamid). This compound is known from EP-A298 196.

Furthermore, preference is given to compounds of the formula I in whichR¹ and R² together with the bridging C═C double bond form a3,4-difluoromethylenedioxyphenyl group.

In addition, preference is given to compounds of the formula I in whichR⁴ is 3,5-dimethylisoxazol-4-yl.

Particular preference is given to the compounds of the formula Ib inwhich X is halogen.

Halogen denotes fluorine, chlorine, bromine and iodine.

Particular preference is given to compounds of the formula Ib in which Xis bromine or chlorine.

Preference is given to compounds of the formula II′ [sic] which areS-configured in the amino acid moiety. These compounds correspond to theformula II′:

According to a further preferred embodiment, compounds of the formulaII′ are used where the carbon adjacent to the group R′ is R-configured.These compounds correspond to the formula II″:

The formulae II′ and II″ represent in particular valinamides of theformulae IIa and IIb in which the substituents in each case correspondto one row of the table below:

IIa

IIb

No. Formula R R″ II-1 IIa Br CH(CH₃)₂ II-2 IIa Cl CH(CH₃)₂ II-3 IIa CH₃CH(CH₃)₂ II-4 IIa OCH₃ CH(CH₃)₂ II-5 IIa Br CH(CH₃)CH₂CH₃ II-6 IIa ClCH(CH₃)CH₂CH₃ II-7 IIa CH₃ CH(CH₃)CH₂CH₃ II-8 IIa OCH₃ CH(CH₃)CH₂CH₃II-9 IIb F CH(CH₃)₂ II-10 IIb Cl CH(CH₃)₂ II-11 IIb Br CH(CH₃)₂ II-12IIb F CH(CH₃)CH₂CH₃ II-13 IIb Cl CH(CH₃)CH₂CH₃ II-14 IIb BrCH(CH₃)CH₂CH₃

Particular preference is given to compounds II-3, II-9 and to compoundII-15:

For the compounds II-1 to II-15, the configuration according to formulaII′ is preferred.

Particular preference is given to mixtures of the compounds of theformula Ia which comprise as second component II-3 (common name:iprovalicarb), II-9 or II-15.

When preparing the mixtures, it is preferred to employ the pure activecompounds I and II, to which further active compounds against harmfulfungi or against other pests, such as insects, arachnids or nematodes,or else herbicidal or growth-regulating active compounds or fertilizerscan be admixed.

The mixtures of the compounds I and II, or the compounds I and II usedsimultaneously, together or separately, exhibit outstanding activityagainst a wide range of phytopathogenic fungi, in particular from theclasses of the Ascomycetes, Basidiomycetes, Phycomycetes andDeuteromycetes. Some of them act systemically and can therefore also beemployed as foliar- and soil-acting fungicides.

They are especially important for controlling a large number of fungi ina variety of crop plants, such as cotton, vegetable species (e.g.cucumbers, beans, tomatoes, potatoes and cucurbits), barley, grass,oats, bananas, coffee, maize, fruit species, rice, rye, soya, grapevine,wheat, ornamentals, sugar cane, and a variety of seeds.

They are particularly suitable for controlling the followingphytopathogenic fungi: Erysiphe graminis (powdery mildew) in cereals,Erysiphe cichoracearum and Sphaerotheca fuliginea in cucurbits,Podosphaera leucotricha in apples, Uncinula necator in grapevines,Puccinia species in cereals, Rhizoctonia species in cotton, rice andlawns, Ustilago species in cereals and sugar cane, Venturia inaequalis(scab) in apples, Helminthosporium species in cereals, Septoria nodorumin wheat, Botrytis cinera (gray mold) in strawberries, vegetables,ornamentals and grapevines, Cercospora arachidicola in groundnuts,Pseudocercosporella herpotrichoides in wheat and barley, Pyriculariaoryzae in rice, Phytophthora infestans in potatoes and tomatoes,Plasmopara viticola in grapevines, Pseudoperonospora species in hops andcucumbers, Alternaria species in vegetables and fruit, Mycosphaerellaspecies in bananas and Fusarium and Verticillium species.

They can furthermore be employed in the protection of materials (forexample the protection of wood), for example against Paecilomycesvariotii.

The compounds I and II can be applied simultaneously, that is eithertogether or separately, or successively, the sequence, in the case ofseparate application, generally not having any effect on the result ofthe control measures.

The compounds I and II are usually employed in a weight ratio of from20:1 to 1:20 , in particular from 10:1 to 1:10 , preferably from 5:1 to1:5.

Depending on the kind of effect desired, the application rates of themixtures according to the invention are, in particular in agriculturalcrop areas, from 0.01 to 8 kg/ha, preferably 0.1 to 5 kg/ha, inparticular 0.1 to 3.0 kg/ha.

The application rates of the compounds I are from 0.01 to 1 kg/ha,preferably 0.05 to 0.5 kg/ha, in particular 0.05 to 0.3 kg/ha.

Correspondingly, in the case of the compounds II, the application ratesare from 0.01 to 1 kg/ha, preferably 0.02 to 0.5 kg/ha, in particular0.05 to 0.3 kg/ha.

For seed treatment, the application rates of the mixture are generallyfrom 0.001 to 250 g/kg of seed, preferably 0.01 to 100 g/kg, inparticular 0.01 to 50 g/kg.

If phytopathogenic harmful fungi are to be controlled, the separate orjoint application of the compounds I and II or of the mixtures of thecompounds I and II is effected by spraying or dusting the seeds, theplants or the soils before or after sowing of the plants, or before orafter plant emergence.

The fungicidal synergistic mixtures according to the invention or thecompounds I and II can be formulated for example in the form ofready-to-spray solutions, powders and suspensions or in the form ofhighly concentrated aqueous, oily or other suspensions, dispersions,emulsions, oil dispersions, pastes, dusts, materials for broadcasting orgranules, and applied by spraying, atomizing, dusting, broadcasting orwatering. The use form depends on the intended purpose; in any case, itshould ensure as fine and uniform as possible a distribution of themixture according to the invention.

The formulations are prepared in a known manner, e.g. by adding solventsand/or carriers. The formulations are usually admixed with inertadditives, such as emulsifiers or dispersants.

Suitable surfactants are the alkali metal salts, alkaline earth metalsalts and ammonium salts of aromatic sulfonic acids, e.g. ligno-,phenol-, naphthalene- and dibutylnaphthalenesulfonic acid, and of fattyacids, alkyl- and alkylarylsulfonates, alkyl sulfates, lauryl ethersulfates and fatty alcohol sulfates, and salts of sulfated hexa-, hepta-and octadecanols, or of fatty alcohol glycol ethers, condensates ofsulfonated naphthalene and its derivatives with formaldehyde,condensates of naphthalene or of the naphthalenesulfonic acids withphenol and formaldehyde, polyoxyethylene octylphenol ether, ethoxylatedisooctyl-, octyl- or nonylphenol, alkylphenol [sic] or tributylphenylpolyglycol ethers, alkylaryl polyether alcohols, isotridecyl alcohol,fatty alcohol/ethylene oxide condensates, ethoxylated castor oil,polyoxyethylene alkyl ethers or polyoxypropylene [lacuna], laurylalcohol polyglycol ether acetate, sorbitol esters, lignosulfite wasteliquors or methylcellulose.

Powders, materials for broadcasting and dusts can be prepared by mixingor jointly grinding the compounds I or II or the mixture of thecompounds I and II with a solid carrier.

Granules (e.g. coated granules, impregnated granules or homogeneousgranules) are usually prepared by binding the active compound, or activecompounds, to a solid carrier.

Fillers or solid carriers are, for example, mineral earths, such assilicas, silica gels, silicates, talc, kaolin, limestone, lime, chalk,bole, loess, clay, dolomite, diatomaceous earth, calcium sulfate,magnesium sulfate, magnesium oxide, ground synthetic materials andfertilizers, such as ammonium sulfate, ammonium phosphate, ammoniumnitrate, ureas, and products of vegetable origin, such as cereal meal,tree bark meal, wood meal and nutshell meal, cellulose powders or othersolid carriers.

The formulations generally comprise from 0.1 to 95% by weight,preferably 0.5 to 90% by weight, of one of the compounds I or II or ofthe mixture of the compounds I and II. The active compounds are employedin a purity of from 90% to 100%, preferably 95% to 100% (according toNMR spectrum or HPLC).

The compounds I and II, the mixtures, or the corresponding formulations,are applied by treating the harmful fungi, their habitat or the plants,seeds, soils, areas, materials or spaces to be kept free from them witha fungicidally effective amount of the mixture, or of the compounds Iand II in the case of separate application.

Application can be effected before or after infection by the harmfulfungi.

USE EXAMPLE

The synergistic activity of the mixtures according to the invention wasdemonstrated by the following experiments:

The active compounds, separately or together, were formulated as a 10%emulsion in a mixture of 63% by weight of cyclohexanone and 27% byweight of emulsifier, and diluted with water to the desiredconcentration.

Evaluation was carried out by determining the infected leaf areas inpercent. These percentages were converted into efficacies. The efficacy(W) was calculated as follows using Abbot's formula:W=(1−α)·100/β

-   -   α corresponds to the fungal infection of the treated plants in %        and    -   β corresponds to the fungal infection of the untreated (control)        plants in %

An efficacy of 0 means that the infection level of the treated plantscorresponds to that of the untreated control plants; an efficacy of 100means that the treated plants were not infected.

The expected efficacies of the mixtures of the active compounds weredetermined using Colby's formula [R. S. Colby, Weeds 15, 20-22 (1967)]and compared with the observed efficacies.E=x+y−x·y/100  Colby's formula

-   -   E expected efficacy, expressed in % of the untreated control,        when using the mixture of the active compounds A and B at the        concentrations a and b    -   x efficacy, expressed in % of the untreated control, when using        active compound A at a concentration of a    -   y efficacy, expressed in % of the untreated control, when using        active compound B at a concentration of b.

Use example: Protective activity against late blight of tomatoes causedby Phytophthora infestans

Leaves of potted plants of the cultivar “GroBe Fleischtomate St. Pierre”were sprayed to runoff point with an aqueous suspension which had beenprepared from a stock solution comprising 10% of active compound, 85% ofcyclohexanone and 5% of emulsifier. The next day, the leaves wereinfected with a cold aqueous zoospore suspension of Phytophthorainfestans of a density of 0.25×10⁶ spores/ml. The plants were thenplaced in a water-vapor-saturated chamber at temperatures between 18° C.and 20° C. After 6 days, the late blight on the untreated, but infectedcontrol plants had developed to such an extent that the infection couldbe determined visually in %.

TABLE A Individual active compounds Active compound concentration inEfficacy in % of the spray liquor the untreated Example Active compound[ppm] control 1 Control (85% infection) 0 (untreated) 2 Ia 0.2 82 0.1 700.05 53 3 Ib.1 0.2 87 0.1 73 0.05 47 4 II-3 0.2 70 0.1 53 0.05 29 5 II-90.1 82 0.05 70

TABLE B Combinations according to the invention Active compound mixtureconcentration mixing Observed Calculated Example ratio efficacyefficacy*) 6 Ia + II-3 100 86 0.1 + 0.1 ppm 1:1 7 Ia + II-3 100 660.05 + 0.05 ppm 1:1 8 Ia + II-3 100 79  0.1 + 0.05 ppm 2:1 9 Ia + II-3100 87  0.2 + 0.05 ppm 4:1 10 Ia + II-3 100 78  0.05 + 0.1 ppm 1:2 11Ia + II-3 100 86 0.05 + 0.2 ppm  1:4 12 Ia + II-9 100 86 0.05 + 0.05 ppm1:1 13 Ia + II-9 100 91  0.1 +0.05 ppm 2:1 14 Ia + II-9 100 92 0.05 +0.1 ppm  1:2 15 Ib.1 + II-3   100 87 0.1 + 0.1 ppm 1:1 16 Ib.1 + II-3  100 62 0.05 + 0.05 ppm 1:1 17 Ib.1 + II-3   100 81  0.1 + 0.05 ppm 2:118 Ib.1 + II-3   100 91  0.2 + 0.05 ppm 4:1 19 Ib.1 + II-3   100 750.05 + 0.1 ppm  1:2 20 Ib.1 + II-3   100 84 0.05 + 0.2 ppm  1:4 21Ib.1 + II-9   100 84 0.05 + 0.05 ppm 1:1 22 Ib.1 + II-9   100 92  0.1 +0.05 ppm 2:1 23 Ib.1 + II-9   100 91 0.05 + 0.1 ppm  1:2 24 Ib.1 +II-9   100 94 0.05 + 0.2 ppm  1:4 *) calculated using Colby's formula

The test results show that, for all mixing ratios, the observed efficacyis greater than the efficacy which had been calculated beforehand usingColby's formula.

1. A fungicidal mixture, comprising A) the imidazole derivative of theformula Ia

and B) valinamides of the formula II,

 in which  R′ is phenyl, which is substituted in the 4-position byhalogen or C₁-C₄-alkoxy, is 1- or 2-naphthyl, or is benzothiazol-2-yl,which is substituted in the 6-position by halogen; and  R″ isC₃-C₄-alkyl; in a synergistically effective amount.
 2. A fungicidalmixture as claimed in claim 1, wherein the weight ratio of the imidazolederivative Ia to the valinamides II is from 20:1 to 1:20.
 3. A methodfor controlling harmful fungi, which comprises treating the harmfulfungi, their habitat or plants, seeds, soils, areas, materials or spacesto be kept free from the fungi with the fungicidal mixture defined inclaim
 1. 4. A method as claimed in claim 3, wherein the imidazolederivative of the formula Ia is applied in an amount of from 0.01 to 2.5kg/ha.
 5. A method as claimed in claim 3, wherein the valinamides of theformula II are applied in an amount of from 0.01 to 10 kg/ha.